The present invention refers to a device for aligning glass sheets for its thermal treatment in an annealing lehr, and more specifically, to a device for aligning glass sheets used for the manufacture of windshields or automobile windows for thermal treating in an annealing lehr.
During the tempering and bending process of windshields or automobile windows, the glass sheets, once that these has been cut in accordance with the desired shape, these are placed in a loading station in order to be transported by means of a roller conveyor through an annealing lehr, wherein these are subjected to a tempering, bending and cooling process.
However, one of the main problems of the bending and tempering process is that the glass sheets should be aligned in a precise position on the loading station, since that, during the transportation through the lehr, should coincide with the periphery of a bending mold in order to provide a required curvature to the glass.
The alignment of the glass is critical part of the process, since that, in case of a disalignment or a mis-oriented of the sheet, an erroneous curvature on the glass sheet can be provided.
At the present, exist already patents that describes the alignment of glass sheets on a roller conveyor, for example, the U.S. Pat. No. 4,058,200 issued to Robert G. Frank, which refers to an apparatus for aligning and orienting moving glass sheets immediately prior to their treatment. This invention is specially suitable for use with glass sheets heated while conveyed through a furnace on a roller conveyor where the glass becomes misaligned or mis-oriented prior to entry into a shaping station. The apparatus includes a pair of truncated conical rollers which engage the edge of the glass sheet and, due to their shape, substantially reduce chipping thereof. These rollers are mounted on a carriage in a manner to permit lateral movement relative to the carriage by cams. The carriage reciprocates along the path in a manner to move with the sheets. As the carriage returns, the glass engaging rollers are raised and laterally retracted so as to avoid contact with the oriented glass sheet.
The U.S. Pat. No. 4,493,412 issued to Richard J. Krehnovi, is referred to a glass sheet positioning apparatus for conveyor platform. In this patent, the flat glass sheets are horizontally conveyed and oriented in a precise location. Vertical stops pins removably affixed to a table attached to one end of the apparatus arrest the leading edge of the moving article where-upon pins removably mounted in a pair of transversely movable tables advance toward the article substantially normal to its arrival direction, thus engaging the edges of the article and orienting it in a vise-like manner. Lastly, adjustable pins mounted in a vertical and longitudinally moving table engage the trailing edge of the article and urge it toward the stops pins, thus orienting and aligning the article in a precise position relative to a fixed reference point. The apparatus is particularly adapted to the precise orientation and alignment of pattern cut sheets of glass to be removed from a conveyor platform by a robot.
Finally, the U.S. Pat. No. 4,895,244 issued to Jeffrey R. Flaugher is referred to an apparatus for aligning glass sheets moving on a conveyor line prior to shaping on a bending apparatus. The apparatus includes a pair of stops for engaging the leading edge of the glass sheets and a pair of pushers for engaging the end edges of the glass sheets to align the glass sheets with respect to a reference line.
Notwithstanding that already exists apparatuses for aligning and orienting the glass sheets, one of the main problems is that the stops that aligns the glass sheets are manufactured of nylon in order to avoid the contact of metal with the glass. However, due to that the exposing part of nylon that is in contact with glass is fixed, after certain number of handling operations, the nylon this is in contact with the glass is gradually wear down, which provokes a disalignment of the glass sheet.
With the finality of improving the adjust and to extend the useful operation life of the apparatuses for aligning glass sheets on a roller conveyor, the present invention is referred to a device for aligning glass sheets for the manufacture of windshields or automobile windows. This device being adaptable to a loading station for glass sheets, said device comprising, a supporting structure; an antirotation cylinder-piston assembly of single-acting which attached to the supporting structure; a retention member connected to the piston for supporting or release the edge of a glass sheet, said retention member having a forward movement for supporting the edge of the glass sheet and a backward movement for releasing said glass sheet; and a conical circumferential piece, for example, made of nylamid material, which is attached to the supporting structure over and above of said retention member, in order to facilitate the centering and sliding of the glass sheet toward the retention member. In this way, the glass sheet is placed between various alignment devices in a loading station, in such way that, the edges of the glass sheet be slidable on the surface of the conical circumferential piece until the glass sheet is centered and aligned on the retention member of the device of the present invention.
Once that the glass sheet is centered on the various devices, the cylinder-piston assembly of each device is operated and the retention member has a backward movement and so, the glass sheet is released on a roller conveyor, which will transport the glass sheet toward a bending and tempering process of glass sheets.
It is a first objective of the present invention to provide a device for aligning glass sheets on a roller conveyor, which increases the number of operations in the handling of glass sheets, providing a conical circumferential piece, which rotates freely, avoiding that the conical circumferential pieces that are making contact with the glass be changed frequently.
An additional objective of the present invention, is to provide a device for aligning glass sheets on a roller conveyor, that diminish the wear down of the conical circumferential pieces that are making contact with the glass.
Is another objective of the present invention, to provide a device for aligning glass sheets on a roller conveyor, which facilitate the alignment and centering of the glass sheets.
These and other objectives and additional advantages of the present invention will be evident to those persons who are experts in the field of the following detailed description of the invention, which will be made with reference to a specific embodiment of it in an illustrative sense but not one that would limit the invention.